We will test the hypothesis that psychological factors impact decision making, thereby affecting whether and how elderly perform challenging physical activities. In Part I, a correlational study of decision-making, 400 community- dwelling elderly (65 to 84 years) will answer questionnaires about four challenging tasks illustrated by photographs: a bimanual forward reach from a short step-ladder, stepping into a wet bathtub without hands, walking across an icy patch, and crossing a pedestrian crosswalk at a busy intersection. They will then complete questionnaires with regard to: (a) their self-reported task performance, (b) decision making (considerations of positive and negative consequences); (c) self-rated health, functional status, and three psychological variables (self-efficacy, self-esteem, personal mastery) affecting their performance decisions. Physical and cognitive capabilities will each be assessed using three measures. Multiple regression analyses and structural equation models will then be used to test the hypothesis that psychological factors influence the willingness to perform the tasks as well as actual performance on the four tasks. In order to control for factors hypothesized to effect their decision making and performance on these challenging tasks, and to validate further linkages in a proposed 22 parameter model, we will quantify disease and impairment/capacities (physical and cognitive) in this group. In Part II, by experimentally manipulating psychologically variables a subjects of varying age and functional status perform challenging tasks, we will examine causal mechanisms underlying how psychological factors affect observed performance of two Part I tasks: maximum forward reach from raised surface (120 subjects) and stepping onto a slippery surface (120 subjects). This research will field insight into how psychological variables affect decisions made by every elderly individual confronted with performing physically challenging activities. The insights should lead to better interventions for improving quality of life in those who un-necessarily limit their physical activities, and for reducing injury risk in those who continue to perform such tasks.